Audio problem: Just as McClane and Farrell are about to leave the Eastern Power Hub, Farrell goes on a long rant and his mouth does not match the words he is saying. [In the unrated version of the film, the rant concurs with Will's mouth movements, but the mistake is valid for the regular version.]Joel Amos Gordon
Audio problem: As McClane attempts to escape from the car in the lift shaft, a henchman shoots at him. As McClane hides between the seats, he cries, "Motherf**ker!" However, McClane's lips aren't moving. ('Unrated'/'Ultimate Action Edition' version only).
Audio problem: When McClane and Ferral arrive at Woodlawn, Ferral says something about the cooling towers being on the lower floors. As he does, his mouth doesn't move at all. Granted his mouth is blocked for most of it, but you can see a bit of his mouth at points and it's not moving. (01:30:15)Ssiscool